The invention relates to a communication unit having a housing part provided with means for entering information, and a slide cover that is slideable relative to the housing part. In one position the slide cover least partly covers the means for entering information, while said means are freely accessible in another position of the slide cover.
Both sliding covers and pivotal flip covers are widely used to protect the keypad of communication devices against unintended use and against dirt from the environment.
U.S. Pat. No. 4,845,772 describes a phone having a pivotal flip cover that disables the keys when the flip cover is closed. GB Patent No. 2.235.606 discloses a phone having a slide cover carrying a microphone. International design bulletins DM/039951 and DM/039675 show two phones having detachable slides.
Magneto-rheological fluids and electro-logical fluids used as motion controllers in dampers or shock absorbers are well known in applications like automobile clutches, doors or lids. U.S. Pat. No. 4,200,003 shows a rotary viscous damper using a magnetic fluid as the damping medium. In this case the fluid is used to control the rotation motion of a rotor. In U.S. Pat. No. 5,257,681 there is shown a segmented slim blade, where a magnetic field responsive fluid is used for motion control. Japanese patent publication JP-10009329 shows a spring box motion controller with the additional refinement of a completely flat version. An electro-viscous fluid is used for controlling the damping of the rotation of the rotary shaft. In U.S. Pat. No. 5,736,798 a big magnetically controlled rotational damper is shown, where magnets can be moved closer to the fluid for adjustable braking action in exercise machines.
An object of the invention is to provide a communication unit having a slide assembly with means for the slide assembly to be movable along a set of tracks on a housing part of the communication unit, where the slide assembly in an open position allows improved access to the information input means and still provides a good mechanical connection between the slide and the main body of the unit.
According to the invention this is obtained by a communication unit having a housing part provided with a set of converging tracks along which a slide assembly is slideable relative to the housing part. The slide assembly includes a cover part and a spring. The slide cover is moved by the spring, which presses two slide wings of the slide assembly together. According to the preferred embodiment a left slide wing is fastened to the slide cover part, while a right slide wing is flexibly attached to the left wing to be able to glide inside the slide cover part and follow the conical shape of the housing part. In the tracks on the housing part and in the slide assembly wings are bearings, linear bearings, where each linear bearing consists of two guide ways and a set of caged balls (manufactured by e.g. Schneeberger, Switzerland or INA, Germany) between the guide ways.
Preferably the spring is biased in the locked position of the slide. When a release mechanism is released, the slide assembly is moved by the biased spring.
According to another embodiment of the invention the objective is obtained by a communication unit having a housing part provided with a set of tracks along which a slide assembly is slideable relative to the housing part. The housing part is in this embodiment provided with a motor for moving the movable slide assembly along the tracks.
According to a third embodiment of the invention the objective is obtained by a communication unit having a housing part provided with a set of tracks along which a slide assembly is slideable relative to the housing part. In this embodiment a spring box is mounted in the housing part, which is filled with a magneto-rheological fluid, where a gearwheel connected to said spring box moves the slide assembly. The slide assembly include two magnets, which affects the fluid in the spring box causing a damping or/and an accelerating effect on the slide assembly. A first magnet is placed so it is near the spring box in the closed position of the slide cover part, and a second magnet is placed so it is near the spring box in the open position of the slide cover part. The spring box housing may be built with polymer composites to make it lighter. According to an alternative embodiment the spring box could be mounted on the slide assembly, while the two magnets could be mounted on the housing part.
Another object of the invention is to provide a communication unit having a slide assembly with means for the slide assembly to be movable along a set of tracks on a housing part of the communication unit. The slide assembly allows, in an open position, improved access to the information input means and still provides a good mechanical connection between the slide and the main body of the unit. The slide assembly includes means for reducing the friction, which occurs when the slide assembly moves between its two end positions, the open position and the closed position.
According to an embodiment of the invention this object is obtained by a communication unit having a housing part provided with a set of tracks along which a slide assembly is slideable relative to the housing part, and the slide assembly includes a cover part and two slide assembly wings. The means for reducing the friction are linear bearings, which are located in the tracks on each side of the housing part and in the corresponding tracks on the slide assembly wings. Each linear bearing includes two guide ways and a set of caged balls between the guide ways.
According to another embodiment of the invention the means for decreasing the friction is an internally lubricated polycarbonate on the sliding surfaces on both the housing part and the slide assembly.
It is finally an object of the invention to provide a method for producing a slide assembly for a communication unit with means for decreasing the friction between the sliding surfaces in the communication unit.
According to a preferred embodiment of the invention, this object is obtained by having linear bearings, which are located in the tracks on each side of the housing part and in the corresponding tracks on the slide assembly wings. Each linear bearing includes two guide ways and a set of caged balls between the guide ways.
According to an embodiment of the invention this object is obtained by a two shot moulding method where the slide assembly is produced in two steps. With a first shot injection moulding step the main part of the housing part and the slide assembly are produced by using an ABS/PC blend, and in a second injection moulding step the sliding surfaces are produced by using an internally lubricated polycarbonate.
An alternative embodiment of the invention is to form the internally lubricated polycarbonate as a film or a plate, and place this on the sliding surfaces. The sliding surface is then produced in the first injection moulding step.